UAV-Enabled Wireless Power Transfer for Mobile Users: Trajectory Optimization and Power Allocation

This paper studies an unmanned aerial vehicle (UAV)-enabled wireless power transfer system (WPTS) for mobile users, in which a UAV-installed energy transmitter (ET) is deployed to broadcast wireless energy for charging mobile users functioned as energy receivers (ERs) on the ground. Different from the most of the existing research on wireless energy transfer, a dual-dynamic scenario is proposed where a flying UAV transmits wireless power to charge multiple ground mobile users simultaneously. To explore the adjustable channel state influenced by the UAV’s mobility, the UAV’s power allocation and trajectory design are jointly optimized. For the sake of the fairness, we consider the maximum of the minimum of the energy harvested among the nodes on the ground during a finite charging period. The formulated problem above is a non-convex optimization on account of the UAV’s power limit and speed constraint. An algorithm is proposed in the paper to jointly optimize power and trajectory. Simulation results indicate our design improves the efficiency and fairness of power transferred to the ground nodes over other benchmark schemes.